Sensor substitution

[ivconic]

15.1.2017. I got note from his wife RIP!

Sad to hear that!
6-7 years ago i exchanged several emails with him.
He was more than polite and highly professional person.
God rest his soul!

[soverey]

Hi to all
Mr. Bill Speake is dead and now is problem where to buy this sensors. I try to make it, but there is simple no information. I try to measure coil resistence (FB). FGM3 frim 3.sensors I got 3. diferent result. Same with FGM-1. It look there is not same number of turns. I have no idea why.
Have someone more information?

BR Simon

Sorry to hear that, may he rest in peace. I did ordered 2 sensors from him last December. Very nice person.

[homefire]

Another Great taken by time. It gets us all in the end. Messed Up Deal.

[Idefix]

Hello all.
The thread is a bit old, but may be ..

About the speake sensor, does someone knows what kind of core is used inside ?
soft iron ? Ferrite? Permalloy?

[kolyay]

Hello all. The thread is a bit old, but may be .. About the speake sensor, does someone knows what kind of core is used inside ? soft iron ? Ferrite? Permalloy?

I think permalloy 80...82 (Ni%) or amorphous alloy. I made permalloy using, but sensor gave a little range (50...80 kHz). Permalloy used 79 (Ni%), gtrip gauge 0x08 mm.

[Idefix]

Hi
thanks for answering.
What do you mean with "gtrip gauge 0x08 mm " ?

I have made some runs on spice, to check the behaviour.
I now need some info about the core, material used , and dimensions , like sheet core , or cylindrical core.
the xray picture in the thread doesnt allow to learn about the shape of the core.

[kolyay]

Hi thanks for answering. What do you mean with "gtrip gauge 0x08 mm " ?

thickness 0,08mm. I think need 0.02...0,05 mm. I do not know what kind of core there is.

I have made some runs on spice, to check the behaviour. I now need some info about the core, material used , and dimensions , like sheet core , or cylindrical core. the xray picture in the thread doesnt allow to learn about the shape of the core.

https://jpegbay.com/gallery/006775754-.html#1

[Altra]

I found the notes from my Speake sensor core. The alloy part measured 3mm wide x 40mm long and was sandwiched between thin fiberglass strips. If you find the correct alloy please post the information. I found that the anti-theft tag material ("Metglas") would not oscillate with the Speake circuit.

[Idefix]

Thanks for the picture. Very useful, it clarifies the x ray picture .
About the core, if I understand, it is a cylindrical core of 3 mm, length 40 mm, wound with wire, and after, there is some fiberglass roll over, and,some alloy again ?
Is it exact?

[Altra]

The core is some kind of perma - alloy metal foil. Kolyay described as .08 mm thick. Assuming he is correct the core would measure 3 mm wide X 40mm long X 0.08mm thick. This foil is sandwiched between pcb material with the copper removed. All together with the foil and pcb strips it measures. 3 mm wide X 50 mm long by 1.5mm thick. Not round

[Idefix]

OK. It is more clear .

The difficulty will to found some permalloy.
I have an old TV set ready to go to the garbage, I think that there is a sheet of permalloy around the cathodic tube. I will have a look.

I will post as soon as I have made something running.

[Altra]

Another source to check, some toroids are "tape wound" of permalloy foil. One might be able to crack open the outer shell and unravel the tape. I recall seeing one used in a GFI receptacle.

[waltr]

Another source to check, some toroids are "tape wound" of permalloy foil. One might be able to crack open the outer shell and unravel the tape. I recall seeing one used in a GFI receptacle.

I have a spool of Metglas 2705M. It is 0.1 inch wide and 0.002 inch thick.
Data sheet:
https://metglas.com/wp-content/uploa...l-Bulletin.pdf

Not sure if this is a permalloy. If this will work I can send you a couple feet of it.

[Atul Asthana]

waltr, thanks a lot.

There is a manufacturer of amorphous metal tape/toroids in India (http://uaml.in/). I have requested them for some samples.

In case, I am not able to find anything, I will be grateful to use your generosity.

Thanks once again.

[Altra]

I have a spool of Metglas 2705M. It is 0.1 inch wide and 0.002 inch thick.
Data sheet:
https://metglas.com/wp-content/uploa...l-Bulletin.pdf

Not sure if this is a permalloy. If this will work I can send you a couple feet of it.

I have a roll of Metglas also, that I purchased from Less Emf. The 2705M is supposedly the same material used in the anti-theft tags. I did alot of experiments. What I found was when used on the bench. It tested very sensitive in simple oscilator circuits. When ever I tried potting or laminating the metglas foil. The sensitivity would drop due to mechanical damping. Apparently it needs to be semi-free to vibrate. Maybe some kind of heat treating would cure this problem?

This video mentions the same about leaving it free to oscilate.

https://www.youtube.com/watch?v=dP84iJlQCDI

I have some Ultraperm 80 which is 80.3% nickel, 14.3% iron and 5.4% molybdenum. This is working in the Speake FGM-3 circuit.
I am still trying to work out the correct number of turns for the primary coil and feedback

Ultraperm 80 on ebay

https://www.ebay.com/itm/MuMetal-Ult...-/152045122881